1. Field of the Invention
The present invention relates to a spectroscopic image input system for obtaining the spectrum data of an image of an object.
2. Description of the Prior Art
Acquiring and then analyzing the spectrum data of an object is very effective in obtaining detailed information about the object. On the basis of spectrum data, it is possible to distinguish readily even colors that cannot be distinguished by the naked eye. Accordingly, by obtaining the spectrum data of an object, it is possible to obtain detailed information about the object that helps, for example, to distinguish readily natural and artificial flowers or check how ripe fruit is, which would be impossible through inspection by appearances. Moreover, it is also possible to check unevenness in hues and brightness on liquid crystal displays, or to compare precisely the colors of different inks.
To meet such requirements, in recent years, spectroscopic image input systems for obtaining the spectrum data of an object have been developed with more zeal than ever.
Conventional spectroscopic image input systems include arrangements that obtain the spectrum data of all the pixels of an image at a stroke by the use of an interferometer and arrangements that obtain the spectrum data of the pixels of an image line by line by the use of a spectroscopic prism.
However, arrangements that obtain the spectrum data of all the pixels at a stroke require the use of a high-precision interferometer having an optical-path width corresponding to the size of the image to be processed, and are thus expensive. Moreover, arrangements of this type take much time in data processing because they need to process a large amount of data, and in addition require an expensive means for processing a large amount of data.
On the other hand, arrangements that obtain the spectrum data line by line take much time to obtain data because, to obtain two-dimensional data, they need to scan in a direction perpendicular to the lines, and take much time also in data processing because they need to process a large amount of data resulting therefrom. Moreover, they also require an expensive means for processing a large amount of data.
Separately from these conventional examples, a spectroscopic image input apparatus for obtaining the spectroscopic information of the surface of the moon has been proposed. This apparatus is composed of an imaging portion that conducts surface observation with high spatial resolution and a profiling portion that conducts observation along a given observation line with high wavelength resolution. The imaging portion captures an image, and, for a part of the captured image, the profiling portion obtains spectroscopic data with high wavelength resolution. However, this apparatus is intended for use aboard a satellite, and therefore its imaging portion achieves surface observation by exploiting, as scanning movement, the movement of the satellite relative to the surface of the moon. Thus, it takes much time to obtain the data of a given area.
Accordingly, even if the profiling portion is made to conduct observation of only a desired part of the result of surface observation conducted by the imaging portion so that the result of high-wavelength-resolution observation in a desired position will be obtained as quickly as possible, it takes, after all, much time to obtain the result of high-wavelength-resolution observation in a desired position because it takes much time for the imaging portion to conduct surface observation as described above.
Japanese Laid-Open Patent Application No. H9-178563 (corresponding to U.S. Pat. No. 5,751,420) discloses an apparatus that takes a picture of an object so as to obtain the spectrum data of the object within a small portion in a desired position of the image taken. With this apparatus, it is possible to obtain rough information of an entire object from the image taken and then determine, on the basis of this rough information, in what portion of the image to obtain spectrum data to obtain detailed information. Here, it takes little time to take the picture, and, since spectrum data needs to be obtained only in a desired position, it takes far less time than ever to obtain the spectrum data. Thus, it is possible to obtain detailed information in a very short time. Moreover, since the amount of the spectrum data is small, it is easy to process it.
However, with this apparatus disclosed in the above-mentioned Japanese Laid-Open Patent Application, the user is required, while the image taken is being displayed, to observe the image and determine in what portion thereof to obtain detailed information. Thus, it is impossible to obtain spectrum data without the help of the user. Accordingly, this apparatus is unfit to be used continuously for a long time, and cannot exhibit its ability to the full in cases where there are a large number of target objects and their data needs to be obtained continuously. Moreover, it tends to take much time to determine in what portion of the image to obtain spectrum data.
Moreover, to determine properly where to obtain spectrum data, the user needs to be sufficiently skilled, because an inappropriate determination makes it impossible to obtain useful information from the spectrum data obtained. Acquiring spectrum data in a number of portions will make it possible to obtain useful information, but this increases the time required to obtain the spectrum data, and thus makes it impossible to obtain data in a short time.
Furthermore, in conventional apparatuses, the spectrum data obtained is presented in the form of a graph displayed on a personal computer or the like, and the user is required to analyze the spectrum data by examining the graph displayed. Thus, it takes much time to analyze the spectrum data, and the quality of such analysis tends to vary according to how skilled the user is.
An object of the present invention is to provide a spectroscopic image input system that has a simple structure but nevertheless permits the spectrum data of an object to be obtained properly and in a short time, and to provide a spectroscopic image input system that analyzes the obtained spectrum data quickly and with stable quality.
To achieve the above object, according to one aspect of the present invention, a spectroscopic image input system is provided with: an image data capturing apparatus for capturing the image data of an object within a predetermined area and with predetermined wavelength resolution by using an image-sensing device; a spectrum data obtaining apparatus for obtaining the spectrum data of the object within a smaller area than the predetermined area in which the image is captured and with higher wavelength resolution than the wavelength resolution of the image data capturing apparatus; and a determination section for determining a portion of the object to obtain the spectrum data by the spectrum data obtaining apparatus on the basis of the image data captured by the image data capturing apparatus.
This system helps capture the image data of an object and also obtain the spectrum data thereof with high wavelength resolution. The image data can be captured by the use of a two-dimensional image-sensing device, and thus doing that takes little time. Moreover, the spectrum data is obtained only within a small area, and thus doing that takes less time and requires only a simple configuration in the spectrum data obtaining apparatus.
The spectrum data is obtained on the basis of the image data. Here, in what portion of the object to obtain spectrum data is determined by the system itself, and thus the user is not required to make such a determination or to be skilled enough to do so. Accordingly, it is possible to determine quickly where to obtain spectrum data and obtain without fail spectrum data that conveys useful information. Furthermore, it is possible to capture the image data and obtain the spectrum data automatically.
According to another aspect of the present invention, a spectroscopic image input system is provided with: an image data capturing apparatus for capturing the image data of an object within a predetermined area and with predetermined wavelength resolution by using an image-sensing device; a spectrum data obtaining apparatus for obtaining the spectrum data of the object within a smaller area than the predetermined area in which the image is captured and with higher wavelength resolution than the wavelength resolution of the image data capturing apparatus; and an analyzer including a first analysis section for analyzing the image data captured by the image data capturing apparatus and a second analysis section for analyzing the spectrum data obtained by the spectrum data obtaining apparatus.
Also this system helps capture the image data of an object and obtain the spectrum data thereof with high wavelength resolution, requiring, just as described above, less time in capturing the image data and obtaining the spectrum data and a simple configuration in the spectrum data obtaining apparatus. Furthermore, analysis of the image data, i.e. extraction of the rough characteristics of the object over a broad area, and analysis of the spectrum data, i.e. extraction of the detailed characteristics of the object within a limited portion thereof, are performed by the system itself, and thus the user is not required to make any determination. Accordingly, it is possible to analyze the object, i.e. extract the characteristics thereof, quickly and with stable quality at all times.
Both of the systems described above may be so designed that at least a part of the wavelength range of the spectrum data obtained by the spectrum data obtaining apparatus lies outside the wavelength range of the image data captured by the image data capturing apparatus. This makes it possible to obtain information that would not be obtained no matter how high the wavelength resolution of the image data may be made. For example, by setting the wavelength range of the image data to be equal to that of visible light and setting the wavelength range of the spectrum data to be equal to that of infrared rays or of visible light plus infrared rays, it is possible to obtain not only information about the appearance of the object but also information that would not been obtained through inspection of the object by appearances.